Please note: I am only a beginner in the Spanish language, so there will be a lot of inaccuracies and mistakes in my presentation.
If you prefer to be taught by professionals and Spanish speaking natives who have much more experience than I do, I would like to point you to the following
excellent and free online courses which I myself have drawn great profit from:
The Language Tutor (Youtube Link)
Spanish From The Roots (Youtube Link)
All these windy introductory speeches aside, I now invite ye to plunge into the topics that interest ye by selectin' a button of yer choice below.